The invention relates to a block-protected braking system for vehicles with the characteristics of the preamble clause of claim 1, as it is known from DE 40 01 017 A1. This known arrangement, however, does not show the connection between the valve block and a pump motor for a pump which delivers a hydraulic fluid.
The term xe2x80x9cblock-protected braking systemxe2x80x9d herein refers to a unit which prevents the blockage of braked wheels of a vehicle and, if required, also the spinning of driven wheels (so-called antislip controlxe2x80x94ASC). Such a unit comprises at least the following assemblies: an electronic controller which generally includes a computer which derives instructions for the control of the braking system depending on measured data (such as e.g. deceleration and acceleration values of the wheels), a valve block which in particular accommodates solenoid valves for controlling the hydraulic fluid in the braking system, with the valves being opened or closed, respectively, in accordance with the instructions generated by the computer, and a pump motor which drives a pump which delivers the hydraulic fluid to the master cylinder and/or the wheel brakes of the vehicle, if the valves are set accordingly.
The system assemblies valve block, pump, and pump motor are often designated as the xe2x80x9chydraulic power unitxe2x80x9d.
The present invention relates to the arrangement, assembly and connection of the cooperating assemblies electronic controller, valve block, pump motor and pump.
From the state of the art a variety of arrangements of the mentioned assemblies of a block-protected braking system is known. Particular reference shall be made to EP-A-0 105 219, DE-A-38 13 138 and DE-A-38 13 139.
With respect to the geometrical arrangement of the above-mentioned components and their electrical and mechanical connections, it is of essential importance to achieve an assembly as compact (minimum space requirement) as possible. Moreover, lines for the electrical connections (in particular cable trees) are to be reduced with respect to circumference and length, and the assembly of the parts must be as simple as possible. In addition, the entire arrangement should be limited to as few components as possible. Moreover, the connection of the individual components shall be electrically and mechanically safe and have a low susceptibility to failures. The subject matter of the present invention implies an improvement with respect to all these technical problems.
In view of the above-mentioned set of technical objects, the electrical and mechanical assembly of the pump motor according to the state of the art need to be improved. It is also to be noted that under the aspect of the above-mentioned mechanical and, especially, electrical safety of assembly and connection of the components, a sealing of the housing which encompasses the components becomes necessary, especially a sealing against humidity, dirt, etc.
EP-A-0 438 553 discloses a valve block where the solenoids of the valves are combined on a common contact carrier which also contains common connectors for connecting the solenoids with the electronic controller of the braking system. However, an integration of the electrical and mechanical assembly of the pump motor is not provided.
From WO 93/08050 A1 an electrohydraulic unit for the pressure regulation in vehicle braking systems is known, where the valve block is connectd with a pump motor for a pump delivering hydraulic fluid. In this arrangement the pump motor, however, is not provided with a shoulder which fits into a recess in the intermediate body.
In view of the technical problems as mentioned the invention improves a block-protected braking system of the above-mentioned type by the characteristics of claim 1.
In that the pump motor (or a housing which accommodates the pump motor) comprises a shoulder which is inserted in an accurately fitting and positive manner into a recess in the intermediate body, and which contains an electrical connection line for connecting the pump motor with the electronic controller, a mechanical and electrical connection of the pump motor with the electronic controller and also with the valve block is obtained simultaneously. The intermediate body serves both as an electrical and a mechanical connecting member for all three assemblies, i.e. the electronic controller, the valve block and the pump motor.
Preferred embodiments of the block-protected braking system are described in the dependent claims.
A particularly consequent application of the inventive design is obtained if the pump motor and the housing of the electronic controller area also connected to one anothr by means of the intermediate body.
Thus, the invention provides for the connection of the electronic controller and the hydraulic power unit (see above) via an intermediate body which carries all the solenoids of the valves of the hydraulic power unit. A direct electrical connection from a printed circuit board of the electronic controller via plug and socket contacts is made to connection lines which lead to the solenoids. These connection lines are accommodated in the intermediate body and electrically insulated therein.
The inventive arrangement of the components is advantageous in that only two seals are required as a protection particularly of the electronic controller against environmental influences (humidity, dirt, etc.), one of which is disposed between the housing of the electronic controller and the other is disposed between the intermediate body and the pump motor. According to a preferred embodiment the latter is a seal between the intermediate body and a shoulder at the pump motor.
The intermediate body which serves to connect the components electrically and mechanically can be manufactured as an economical injection-molded plastic part, with the solenoids together with the electrical conductors being embedded. The electrical conductors can also be manufactured in a simple manner as a punched grid.
It is also advantageous that the braking system according to the invention allows the arrangement of the electronic controller beneath the hydraulic power unit. This enables a particularly compact arrangement of the parts.
According to another preferred embodiment of the invention, the pump motor comprises a shoulder which is independent (spatially separated) of the intermediate body and which accommodates an electrical connection between the electronic controller and the pump motor. This separation between the housing and the valve block on the one hand, and the housing and the pump motor on the other hand, enables a shorter line routing and provides for a better decoupling of the respective signals. Moreover, the intermediate body can be of a simpler design because it is not adapted to encompass the shoulder.
In order to obtain a particularly stable connection between the housing and the valve block and between the the housing and the pump motor which is also reliably sealed against dust, humidity, oil, etc. the housing comprises a first support for the intermediate body and a second support for the shoulder. In a particularly preferred embodiment, the first and the second support are connected with the housing in a dustproof and/or hermetically sealed manner.
In addition, the first and/or the second support can be connected with a printed circuit board in the housing in a dustproof and/or hermetically sealed manner. This allows a further increase of the reliability.
The electric connection between the pump motor and the housing of the electronic controller can also be be made by means of plug and socket contacts, with the second support accommodating plug and socket contacts between the electronic controller and the pump motor.
Each of the first and/or second support is preferably provided with a seal which ensures a dustproof and/or hermetically sealed connection between the valve block or the pump motor and the housing, respectively.
According to a preferred embodiment the intermediate body and/or the shoulder are arranged laterally adjacent to or in a recess in a supporting plate of the valve block or the pump motor, respectively, and provide for the connection between the first or the second support, respectively. In addition, the housing of the electronic controller can be secured at the supporting plate e.g. by means of a suitable screw connection. This is advantageous in that the overall arrangement has a considerably flatter design than the first embodiment because the transverse dimension of the intermediate body is omitted here. Moreover, the cooling function is improved because the housing of the electronic controller is directly contacting the heat conductive (metallic) supporting plate which in turn contacts the heat conductive valve block which is also heat conductive due to the omission of the intermediate body.
In a preferred embodiment the first and/or second support each are encompassed by a seal which bears upon the respective support in an axial and a radial direction, and the intermediate body or the shoulder, respectively, encompasses the respective seal.
The supporting plate can additionally be screwed to the valve block and/or to the pump motor. In particular, this can also be done by means of screw-type formed dampening chamber plugs which are already present a larger volume of the dampening chamber can be provided by a corresponding shape of the dampening chamber plug.